title: Individual oligodendrocytes have only a few hours in which to generate new myelin sheaths in vivo.
abstract: The number of myelin sheaths made by individual oligodendrocytes regulates the extent of myelination, which profoundly affects central nervous system function. It remains unknown when, during their life, individual oligodendrocytes can regulate myelin sheath number in vivo. We show, using live imaging in zebrafish, that oligodendrocytes make new myelin sheaths during a period of just 5 hr, with regulation of sheath number after this time limited to occasional retractions. We also show that activation and reduction of Fyn kinase in oligodendrocytes increases and decreases sheath number per cell, respectively. Interestingly, these oligodendrocytes also generate their new myelin sheaths within the same period, despite having vastly different extents of myelination. Our data demonstrate a restricted time window relative to the lifetime of the individual oligodendrocyte, during which myelin sheath formation occurs and the number of sheaths is determined.
authors.affiliation: Centre for Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK.
authors.forename: Tim
authors.initials: T
authors.lastname: Czopka
authors.forename: Charles
authors.initials: C
authors.lastname: Ffrench-Constant
authors.forename: David A
authors.initials: DA
authors.lastname: Lyons
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D005260:Female; D055786:Gene Knockout Techniques; D049452:Green Fluorescent Proteins / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009186:Myelin Sheath / Q000502:physiology*; D009413:Nerve Fibers, Myelinated / Q000502:physiology; D009420:Nervous System / Q000166:cytology / Q000196:embryology; D009836:Oligodendroglia / Q000502:physiology*; D051076:Proto-Oncogene Proteins c-fyn / Q000235:genetics / Q000502:physiology*; D013116:Spinal Cord / Q000166:cytology / Q000196:embryology*; D059008:Time-Lapse Imaging; D015027:Zebrafish / Q000196:embryology / Q000502:physiology*; D029961:Zebrafish Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D029961:Zebrafish Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; C494957:FYN protein, human; D051076:Proto-Oncogene Proteins c-fyn; C494964:fyna protein, zebrafish